The Bidirectional Four-Switch Buck-Boost Converter With PWM Plus Phase-Shift Control

The bidirectional Four-Switch Buck-Boost (FSBB) converter has the functions of positive output and lower voltage stress. With the pulse width modulation (PWM) plus phase-shift control, all the power switches can realize zero-voltage switching (ZVS). In this paper, a smooth transition control approach for power flow is proposed, which not only ensures smooth reversal of the power flow within one switching cycle, but also realize ZVS for the power switches even after a change in the power flow. To verify the effectiveness of the control method, a prototype with the output power from −5 kW~5 kW bidirectional FSBB converter is built and tested in the lab.